The research extends existing models of the segmental and prosopic planning processes and evaluates an integrated model of both of these aspects of the phonological planning process. Competing models of segmental planning, particularly models of the serial ordering of individual phonemic segments, are evaluated using data form existing corpora of errors from spontaneous speech, supplemented by additional examples to be collected. Models of prosopic planning, particularly the placement of intonational prominences (pitch accents), are evaluated in experimentally-elicited text sentences as well as in a database of prosopically-labelled FM radio speech. Finally, a model of the integration of segmental and prosopic planning is tested with data from prosopic analysis of segmental errors, made possible by collection of a new corpus of tape-recorded errors from spontaneous speech, and from experimentally elicited utterances designed to contrast the effects of syntactic vs. prosopic structure on error patterns. In the course of the work, existing databases of speech errors and of prosopically labelled speech will be enlarged and reorganized in ways that will facilitate their distribution to the research community. A more thoroughgoing understanding of these phonological aspects of the speech production planning process, an their relation both to syntactic/semantic planning on the one hand and to articulatory motor control on the other, will provide advantages in several areas, including an improved theoretical basis for the development of therapeutic treatments for disadvantaged speakers (including the hearing impaired and patients with certain kind of aphasia), a stronger foundation for advances in automatic speech recognition and synthesis that will aid in development of aids for the language and speech handicapped, and a better-grounded approach to effective ways of teaching the prosody of English as a second language.